The Welsh Terrier was developed in Wales in order to hunt badger, fox, otter and other vermin. Like all terriers, he had to have gameness in order to follow these animals into their burrows and fight them when they turned around to attack the dog. Indeed, the majority of these creatures would engage in a fight to the death with dogs that entered their burrows, as they often felt cornered, with no way out but to fight. Terriers not only had to be brave enough to participate in the fight, but also have the tenacity to continue fighting even if they were badly wounded; any sign of weakness and the Welshie was not coming out of the den alive.

This characteristic of going on in spite of serious injury is called "gameness." Certain dogs are actually bred with this quality, while others are not only bred but also trained and conditioned to exhibit gameness. Unfortunately, gameness was seen as a big asset in dog fighting breeds and many of these breeds were conditioned to fight other dogs to the death despite broken bones, severe blood loss and exhaustion. Thankfully, the gameness of Welsh Terriers never landed them in the dog fighting ring; their spirited, courageous temperament, though, was a crucial quality for the hunters who needed the dogs to rid their farms of pesky critters. These dogs can work for hours, without thought to food or water, which is also part of being a game dog.

The gameness that was bred into the Welsh Terrier is still very much present in the breed, though very few are actually used in their original capacity. Welsh Terriers, like all terriers, will never back down from a fight if provoked; some Welshies like to do the provoking, while others are not overly combative dogs. No matter who starts the fight, though, a Welshie is in it for the long haul. They are also not the right dogs with which to use physical force for corrections; many Welshies will feel threatened by the use of physical force and will retaliate, snapping back at their owners and not allowing their owners to "win." Their "I can do anything" attitude that stems from their game dog qualities may frustrate the first time dog owner; it will lead the Welshie to challenge authority and attempt to dominate the household; their lack of fear coupled with their intelligence also makes them cunning escape artists.

As mentioned, it is fortunate for the Welshie that his tenacity has not earned him a spot in the dog-fighting circuit. Indeed, while Welshies have just the right amount of gameness to allow them to excel at their original purpose, the majority of these wire-haired canines are not very "quarrelsome" and tend not to like aggression. They will often be friendly, or at least tolerant, to strangers and animals, and with the right training can be very stable, well-mannered, loving, loyal companions.